Storage Area Networks (SANs) reliably store large amounts of data for an organization. Clusters of storage devices, e.g., FC storage arrays, in one location are called SAN islands and communicate using the FC Protocol. Users accessing a SAN may reside on an Ethernet based Local Area Network (LAN) at another location that may be coupled to an FC server cluster for communication with the FC storage array. To mediate communication between the FC server cluster and the FC storage array, an FC switch network (also called “switched fabric”) is employed.
Recent advances have led to virtualization in SANs resulting in the creation of Virtual SANs (VSANs). VSANs and VLANs remove the physical boundaries of networks and allow a more functional approach. For example, an engineering department VLAN can be associated with an engineering department VSAN, or an accounting department VLAN can be associated with an accounting department VSAN, regardless of the location of network devices in the VLAN or storage devices in the VSAN. In a virtualized environment, virtual devices can move from one place to another without requiring any physical connectivity changes.
Each FC switch or FCoE FC Forwarder (FCF) has a numbered domain that forms the first part of an FCID. The FCID comprises three bytes (Domain.Area.Port) in a frame header to identify source ports of a source device and destination ports of a destination device. When a virtual SAN device logs into the switch fabric it is assigned an FCID with a domain associated with the respective switch. When a virtual SAN device migrates from a first switch to a second switch, the virtual SAN device must log out of the SAN and log back in via the second switch, thereby acquiring a new FCID associated with the domain of the second switch.